Control valves are used to regulate fluid flow in a wide variety of commercial and industrial systems. Today, many control valves include and/or are controlled by automated positioners, which may have the ability to adjust the valve to control fluid flow for a process. Some positioners may even be able to self-calibrate. Down-time incurred to repair and/or replace control valves and/or positioners and/or loss of product from the process due to the low quality produced while a control valve and/or positioner are malfunctioning may increase production costs and decrease efficiencies for the process.
While detection of a problem in a fluid control system may be identified when the quality of a process deteriorates, the source of the problem in the system may not be identifiable in this manner. Fluid control systems include numerous components that can have problems such as failure, leaking, breaking, and/or operating irregularly, such as limit cycles. Problems with systems are typically only detected once a problem occurs. However, once a problem occurs, a process may have already been adversely affected by the problem. Furthermore, some systems may require the control valve to be brought off line for diagnosis, which can interrupt the process. Other systems may allow on-line detection, but may only detect problems after failure or when the system is operating irregularly, which may still harm the process.